<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">       
    <title><%= title %></title>
  
  <link href="http://libs.baidu.com/bootstrap/3.0.3/css/bootstrap.min.css" rel="stylesheet">
  </head>

  <body>

    <div id="container" class="container">
       <% if (locals.success) { %> 
          <div id="alt_sucess" class="alert alert-success"> 
            <%- success %> 
          </div> 
       <% } %> 

      <% if (locals.error) { %> 
        <div id="alt_warning" class="alert alert-warning"> 
          <%= error %> 
        </div> 
      <% } %> 

      <form class="form-signin" role="form" method="post" enctype='multipart/form-data'>
        <h2 class="form-signin-heading">上传文件</h2>
        <input id="fulAvatar" name="fulAvatar" type="file" class="form-control" />     
        <br/>
        <button id="btnSub" class="btn btn-lg btn-primary" type="submit">上 传</button>
      </form>
            
    </div> 
  </body>
</html>

<script src="http://libs.baidu.com/jquery/2.0.0/jquery.min.js"></script>

<script type="text/javascript">
     String.prototype.format = function (args) {
            var result = this;
            if (arguments.length > 0) {
                if (arguments.length == 1 && typeof (args) == "object") {
                    for (var key in args) {
                        if (args[key] != undefined) {
                            var reg = new RegExp("({" + key + "})", "g");
                            result = result.replace(reg, args[key]);
                        }
                    }
                }
                else {
                    for (var i = 0; i < arguments.length; i++) {
                        if (arguments[i] != undefined) {
                            var reg = new RegExp("({)" + i + "(})", "g");
                            result = result.replace(reg, arguments[i]);
                        }
                    }
                }
            }
            return result;
    }

    $(function(){
        $('#btnSub').on('click',function(){           
            var fulAvatarVal = $('#fulAvatar').val(),  
                errorTip = '<div id="errorTip" class="alert alert-warning">{0}</div> ';  

            $("#errorTip,#alt_warning").remove();
            
            if(fulAvatarVal.length == 0)
            {
                $("#container").prepend(errorTip.format('请选择要上传的文件'));                                
                return false;
            }

           var extName = fulAvatarVal.substring(fulAvatarVal.lastIndexOf('.'),fulAvatarVal.length).toLowerCase();

            if(extName != '.png' && extName != '.jpg'){
               $("#container").prepend(errorTip.format('只支持png和jpg格式图片'));                             
               return false;                
            }
            
            return true;                
        })
    });

</script>